posted on 2023-02-23, 19:07authored byAkshay Balachandran, Irfan Majeed Bhat, Ruheena Tabasum, Ghulam Mohd, Mohammad Farooq Wani, Kowsar Majid, Malik Wahid, Saifullah Lone
Water is indispensable for sustaining life on Earth.
Oil–water mixtures/or emulsions from industrial waste and other
sources are a serious environmental concern for both human beings
and aquatic life. Specially treated meshes and textiles with opposing
wettability for oil–water separation have been widely reported
as a solution to this challenge. Nonetheless, such membranes are hindered
by certain drawbacks, including high manufacturing costs, usage of
harmful chemicals, and lack of diverse applicability. Here, we report
a facile method to fabricate Janus oil–water separation membrane
with a controllable pore structure that has a unique directional flux
rate. The superhydrophobic (SHB) layer of the membrane is formed by
transfer-printing (TP) carbon soot particles onto a polydimethylsiloxane
(PDMS)-coated paper surface. Meanwhile, a spin-coated thin layer of
chitosan on the other side of the film served as a hydrophilic (SHL)
and underwater oleophobic face. A pulsed laser beam is used to produce
micropores with conical structures. The separation ability of the
membrane for both light oil–water and heavy oil–water
mixtures is thoroughly investigated. Moreover, the significance of
the pore shape and the size is also elucidated. The flexible Janus
membrane showed high thermal stability and ideal (i.e., 99.8%) separation
efficiency. The membrane can be produced over a 151 cm2 size range. Besides having flexibility and superior performance,
the fabricated membrane is environmentally friendly and economically
viable. This work establishes a scalable basis for efficient and low-cost
oil/water membranes from non-porous substrates.